Coinfection with HIV and Mycobacterium tuberculosis (M. tb) is associated with high rates of active tuberculosis, and possibly an acceleration of the progression of clinical AIDS. Elucidating the interplay of immunopathogenic events that occur as a result of HIV/M. tb coinfection is, therefore, of central importance for understanding the immune sequlae of this coinfection. The simian immunodeficiency virus (SIV)-infected macaque monkey has proven to be an important model for the study of the pathogenesis and treatment of AIDS. The investigators have recently shown that macaques coinfected with SIV and BCG develop a syndrome similar to AIDS virus-related tuberculosis. Employing this SIV/mycobacterium coinfection model, the immunopathogenesis of AIDS virus interactions with mycobacterium and the evolution of tuberculosis will be evaluated. In these studies, the following will be assessed: I. Disease pathogenesis in SIV/BCG coinfected rhesus monkeys. II. CD4+ responses in BCG-infected and SIV/BCG coinfected monkeys. III. CD8+ responses in BCG-infected and SIV/BCG infected monkeys. IV. T gd+ cell responses in BCG-infected and SIV/BCG coinfected monkeys.